Discrete carbon nanotubes with targeted oxidation levels and formulations thereof

Abstract

Discrete, individualized carbon nanotubes having targeted, or selective, oxidation levels and/or content on the interior and exterior of the tube walls are claimed. Such carbon nanotubes can have little to no inner tube surface oxidation, or differing amounts and/or types of oxidation between the tubes' inner and outer surfaces. These new discrete carbon nanotubes are useful in plasticizers, which can then be used as an additive in compounding and formulation of elastomeric, thermoplastic and thermoset composite for improvement of mechanical, electrical and thermal properties.

We claim: 
     
       1. A composition comprising a plurality of discrete multiwall carbon nanotubes, wherein the discrete multiwall carbon nanotubes comprise an interior and exterior sidewall surface, the interior sidewall surface comprising an interior surface oxidized species content and the exterior sidewall surface comprising an exterior surface oxidized species content, wherein the interior surface oxidized species content is at least about 0.01 weight percent relative to carbon nanotube weight and differs from the exterior surface oxidized species content by at least 20%, and as high as 100%. 
     
     
       2. The composition of  claim 1  wherein the plurality of discrete carbon nanotubes comprises a plurality of open ended tubes. 
     
     
       3. The composition of  claim 1  wherein the interior surface oxidized species content is less than the exterior surface oxidized species content. 
     
     
       4. The composition of  claim 1  wherein the interior surface oxidized species content is up to 3 weight percent relative to carbon nanotube weight. 
     
     
       5. The composition of  claim 1  wherein the exterior surface oxidized species content is from about 1 to about 6 weight percent relative to carbon nanotube weight. 
     
     
       6. The composition of  claim 1  wherein the interior and exterior surface oxidized species content totals from about 1 to about 9 weight percent relative to carbon nanotube weight. 
     
     
       7. The composition of  claim 1  wherein the oxygenated species is selected from the group consisting of carboxylic acids, phenols, aldehydes, ketones, ether linkages, and combinations thereof. 
     
     
       8. The composition of  claim 1  wherein the total oxygenated species content of the interior surface and exterior surface comprises from about 1% to 15% by weight of the carbon nanotubes. 
     
     
       9. The composition of  claim 1  in the form of free flowing particles. 
     
     
       10. The composition of  claim 1 , wherein the composition is further mixed with at least one rubber. 
     
     
       11. The composition of  claim 1 , wherein the composition further comprises at least one thermoplastic polymer, at least one thermoplastic elastomer, or combinations thereof. 
     
     
       12. The composition of  claim 1 , wherein the composition further comprises at least one thermoset polymer selected from the group consisting of an epoxy, a polyurethane, and combinations thereof.